Fabrication of nanocrystalline SnO₂ films by Nd:YAG pulsed laser deposition method for gas sensor applications

Nd:YAG Pulse Laser Deposition method (PLD) is successfully utilized for preparing nanostructured Tin Oxide (SnO₂) thin film. This method gives different morphologies of SnO₂ nanostructure where Sn acts as the basis material and the quartz represents the growth substrates. The characterization of morphological, structural, and optical properties is investigated using atomic force microscopy (AFM), X-ray diffraction (XRD), and ultraviolet–visible (UV–Vis) spectrometer. By varying the laser energy from 600 to 900 mJ, different morphologies of SnO₂ thin film structure are examined giving a polycrystalline structure with a thickness range of (120.7–194.1 nm). By increasing laser energy, SnO₂ thin films grain size was increased. The topography of the AFM image exhibits homogenous deposition surface of samples and the particle size increased by increasing laser energies. XRD for SnO₂ nanoparticles displays a pure cube crystalline structure. The transmission and absorption of the prepared thin film samples are influenced by increasing laser energies. The band gap of SnO₂ is reduced by increasing laser energies (3.094–3.775 eV). I–V measurements of the sample prepared with the energy of 600 mJ is more affected than others. The responses of sensor to 5–50 ppm of NO₂ were studied at different laser energies. The sensitivity of thin films to NO₂ gas was examined. The best sensitivity at 900 mJ is 49.8%. So, these results indicate that SnO₂ is a promising material for gas sensor devices.